🎨 Palette: Improve accessibility of text-based icons

[ralksta]

💡 What: Replaced bare text characters (×, ✕, ↗, ↑) acting as icons with accessible screen-reader hidden spans, and added aria-labels to their parent interactive elements.
🎯 Why: Text characters used as icons without proper ARIA attributes are announced confusingly by screen readers (e.g. "times" instead of "Close"). Wrapping them in aria-hidden spans and labeling the buttons makes the UI much more accessible.
📸 Before/After: Visuals remain identical, but screen reader announcements are now descriptive.
♿ Accessibility: Improved keyboard navigation and screen reader support for icon-only buttons across the admin panel and public site.

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PR created automatically by Jules for task 17342062838490501257 started by @ralksta

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